SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e86ebcfb209454168b9cf2bdcce511696c4b7971cb3dcf5d0a7415d6e09c25ce' 
  AND token = 'QH0AyoWypEHHsZtv6sM9QAOb+UrWkzcb47FUiC6BYco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}